3.1. strchr

char *strchr( const char *s, int c);

strchr returns a pointer to first occurrence of c in s or NULL if not present.

The terminating '\0' of s is considered to be part of the string.

For example, to replace all the '/' characters in a string str with '\\':

        char *p;

        while( (p = strchr( str, '/')) != NULL)
            *p = '\\';

We could improve the efficiency of the above by having strchr start its search for the next match at the position of the current match, i.e.

        char *p = str;

        while( (p = strchr( p, '/')) != NULL)
            *p = '\\';

Since strchr considers the terminating '\0' to be part of the string, it can be used to compute the string length:

        len = strchr( str, '\0') - str;